From Population and Environment, Volume 18, Number 1, September 1996
Humanity has been all too successful in remodeling much of the natural world to serve its own purposes. While this has permitted an unprecedented increase in the number of humans that the Earth will support, it appears that we have exceeded the limits of our natural life-support systems and are rapidly destroying the very resources needed to sustain our existence. We need to turn to the conquest of one last frontier, perhaps the most difficult and dangerous one of all, the mastery of ourselves.
A prosperous, healthy, educated, humane, and democratic form of life for everyone would require the numbers of people consuming the world's resources to come into some sort of reasonable balance with those resources. A brief look at the list of pressing world problems will make it obvious that the present world population is already far greater than can be sustained, even at present levels of misery, for very many more generations.
Modern economic systems have an absolute dependence on massive utilization of fossil fuels which are being consumed at an extravagant rate, and which, of course, are not being renewed. Severe problems exist in finding adequate replacements for the enormous amounts of energy represented by this rapidly diminishing resource. Meanwhile, the carbon dioxide being produced threatens to alter the climate of the Earth via the greenhouse effect, with possible dramatic rises in sea level, bleaching and destruction of coral reefs, and the inundation of heavily populated, and often agriculturally vital, coastal areas. Soil erosion is removing topsoil 20 to 40 times as rapidly as it is being replenished at the same time that burgeoning populations require more and more food, and dwindling forests are cleared to provide the necessary extra crop land. Attempts to farm or graze marginal lands has led to rapid desertification of vast areas. Pollutants in the atmosphere destroy ozone and allow increasing fluxes of ultraviolet light to reach the Earth's surface, not only leading to increases in human skin cancer, but potentially damaging crop plants and reducing agricultural productivity. Many arid areas are irrigated by pumping ground water to the surface, often at rates far in excess of natural recharge-another short-sighted mining of a limited resource that cannot continue for long. Most fisheries are in trouble, with many in a state of near collapse as increasing efforts lead to less and less return, and only a total ban on fishing for a few years will allow recovery of some stocks. Rain forests and old growth forests at all latitudes are rapidly being cleared in the presence of an accelerating demand for wood products. Replanting and natural regrowth lag far behind this destruction, another example of the human propensity to consume resource capital even though the income that could have been derived from it will be needed in the future. Such drastic modifications of the natural environment are accompanied by the extinction of innumerable species, which are vanishing far more rapidly than they can be described and studied.
All of this has had enormous impact on human societies. Famine, war, ethnic strife, and disease are prevalent. Urban ghettoes all over the world teem with people who cannot find useful employment. And as our sympathies are overwhelmed by the sheer mass of human suffering, we turn away from it in despair and cease to respond to the pain of others. Our range of concern narrows and narrows, until only those of our own race, culture, class, and religious group command our sympathies, and we hide behind the gates of closed, guarded communities or the boundaries of tribe or ethnic group and reject all others. This loss of civility impoverishes the spirit and we become indifferent to genocide, starvation, poverty, ignorance, and want, and willing to fight all others for the land, space, and resources needed for the maintenance and expansion of our own group. Death squads proliferate to murder those who are politically active or just inconvenient, and wholesale massacres of "alien" peoples become almost a matter of routine.
All of these things are related to the density of human populations and competition for the resources required for their welfare. With the present world population, many critical resources are being rapidly exhausted, and conflicts between peoples intensify even as unpredictable changes in climate and other factors affecting the livability of the Earth occur.
If we value human culture, treasure civility, democracy, education, health, and a high standard of living in general, there is evident need for not only an end to further growth of the Earth's population, but also an actual and substantial decrease in the number of people the Earth is asked to support.
Many people are highly concerned about the population problem. International conferences are held, efforts are made to persuade world leaders of the seriousness of the problem, educational programs are launched, and family planning services are promoted. The rate of growth of the world population has slowed, and if present trends continue, the population should stabilize after "only" one or two more doublings. This will, no doubt, postpone disaster so that it arrives a few years later than it will if no decrease in growth rate had occurred, but will hardly prevent it.
The necessary decrease in population size is most unlikely to come about voluntarily. Those few countries where the birthrate is slightly below replacement level have generally become quite concerned and some have attempted to raise it again. No nation or cultural group likes to believe that it is dwindling in size. No country wants to feel that it is losing population and that its own people might soon be replaced by fecund foreigners who are clearly all too ready to move into its relatively "empty" spaces. Some countries are moving to defend borders. A decrease in world population will be peaceful only if it affects everyone, and not just the few highly advanced countries where it is found at present.
Rapid reduction in population size is necessary to prevent disaster, but many cultures still value high fertility levels; generations may be required to change these attitudes. These generations we do not have. Most people in the population studies field assume that individual control over reproductive decisions is a basic human right, which can not be tampered with. Yet if exercise of this right is leading to universal disaster, is it not time that the possibility of modifying it was at least considered? When the consequences of any course of action are clearly highly destructive of human welfare, how can one maintain that, never-the-less, people have an innate right to pursue that course of action? I believe that we must not hinder the efforts of governments to restrict reproductive rights among their own people, in order to bring the human population of the Earth and of their country into balance with the longterm carrying capacity at the level of wellbeing that the population wishes to maintain.
It may be argued that the government machinery necessary to monitor the reproductive decisions of individual families and the constant interference with these decisions that would be necessary to maintain a sub-replacement level of fertility can not be afforded by most countries, would be inconsistent with a democratic system of government, and if attempted, would be the source of constant resentment and resistance. Only in highly authoritarian countries like China is an approach to this level of social control feasible, and even in China there appears to be widespread evasion of the rules in many rural areas. This would certainly be a cogent argument if a reduction of average fertility on a global scale required the imposition of government regulations and monitoring. However, there are alternative ways of achieving this objective.
The immune system, which usually functions to protect us from disease, but also is involved in allergies and the rejection of transplanted organs, can be harnessed to contraception (Anderson & Alexander, 1983; Aldhous, 1994). A contraceptive vaccine has been suggested for veterinary use (Miller & Dean, 1993). In this application, the female animal to be sterilized is injected with preparations of the zone pellucida (the outer envelope of the egg cell) from a different species of animal. The injected female responds to this foreign material by producing antibodies against it. These antibodies, however, also recognize the different but related material on her own eggs, a process called "cross-reaction," and attack these, destroying them. The death of these egg cells in the ovary releases the controls on maturation of immature egg cells and they begin to develop. As they approach maturity, they are also recognized by the immune system and destroyed in turn. A run-away cycle of maturation and destruction follows, and within a few months all of the potential egg cells in the animal's ovary have matured and been destroyed, and the female has been nonsurgically sterilized (Skinner, et al, 1984). Such a dramatic procedure would probably have little application in human contraception except in rare cases in which the person concerned wished to be sterilized, and since it would probably induce menopause, is unlikely to be acceptable even then. However, many less absolute contraceptive actions can also be mediated by the immune system.
Many cases of natural infertility occur because the woman produces antibodies against sperm which are recognized as foreign bodies by her tissues (Bronson, et al, 1984). Vaccines could probably be developed that would stimulate more women to produce such antibodies with a corresponding decrease in their fertility (Primakoff, et al, 1988; Primakoff, 1994). In yet another approach, women have been vaccinated with peptide sequences similar to those found in certain hormones involved in reproduction (Talwar et al, 1993; Talwar et al, 1994). Very effective vaccines can be produced by splicing gene segments for the desired peptide sequences into some of the genes of the vaccinia virus (Moss, et al, 1984; Talwar et al, 1993; Talwar et al, 1994) and then using this virus to vaccinate the subject, just as it was used to vaccinate against smallpox. The peptide sequences produced by the virus stimulate antibody formation, the antibodies would cross react with the naturally occurring hormone in the woman's body, and reproduction could be inhibited. Many such alternatives that harness the immune system in the service of contraception are available.
None of these approaches would represent anything other than an addition to the existing armory of contraceptive systems, except for one thing: vaccinia virus is used as a vehicle for stimulating the immune system because it grows locally in the body, and produces an effective stimulus to the immune system, but very rarely spreads spontaneously to other people. However, there is no reason why the required antigens (the substances that stimulate the immune system) could not be introduced into any other virus, such as one of the more than 200 viruses responsible for the common cold, that would spread spontaneously through the population, and thus could serve as a form of infectious contraceptive. Depending on the nature of the antigen used, and their response to it, infected individuals would have more or less reduced fertility levels for longer or shorter periods of time. The effects would necessarily be uneven and it is unlikely that all individuals or populations would be equally affected. If a variety of antigens and viruses were used, however, these differences would average out and the average global fertility could be reduced to any desired level. The technology to carry out this global fertility regulation is not visionary. All of the knowledge and techniques that would be required are available today. Probably the creation and release of a number of different agents would be necessary to reach the desired level of negative population growth, as the effect of any one would be likely to be partial and geographically uneven due to the random accidents of distribution and infection.
Obviously, the use of infectious contraceptive agents raises profound moral and ethical questions, especially that of informed consent and particularly if one assumes that choices about reproduction are intrinsically the sole right of the couples (or often the male partner?) concerned. However, it is quite plain that eventually the growth of human populations will be curbed, and almost certain that negative growth will occur, as population overshoots even the short-range capacity of the Earth to support it, and massive mortality from disease, famine, and genocide takes its course.
We are in the position of a skilled hunter, perched on a mountain ridge, who sees a bus load of children stalled on a curve on an adjacent ridge, while a truck comes hurtling clown the road above, oblivious to the hazard out of sight around the curve below. The hunter has no way of communicating with either party, but he could shoot the truck driver, or blow out a tire, with the almost certain result that the truck will leave the road on the next curve and plunge into the canyon, killing the driver but sparing the bus and its occupants. This is obviously a morally equivocal situation, yet to do nothing, though sparing the hunter any legal responsibility for the death of the trucker, is a morally questionable choice also, since the trucker as well as the children will almost certainly be killed in the collision. Similarly, failing to arrest and reverse the present growth of human populations will almost certainly lead to a devastating collapse in human numbers-the deaths of hundreds of millions or billions of people is quite likely. In the process many major ecosystems will be degraded beyond recovery, innumerable other species will become extinct and many irreplaceable non-living, nonrenewable resources will be exhausted. This will certainly impair the capacity of the Earth to ever again support human societies at a high level of culture and prosperity for any significant number of people, while at the same time insuring that the right to reproduce as one sees fit becomes meaningless as people loose the means to insure their own survival, much less to provide for the children they would like to bear. The trucker will die, whether the hunter shoots him or not. It is Hobson's choice, but we must accept the fact that free choice in reproductive decisions is the one freedom we cannot, in fact, afford, if we are to preserve any of the others.
Aldhous, P. (December 2, 1994). A booster for contraceptive vaccines. Science 266 1484-1486.
Anderson, D.J., & Alexander, N.J. (1983). A new look at antifertility vaccines. Fertility & Sterility 40, 557-571.
Bronson, R., Cooper, G., & Rosenfeld, D. (1984). Sperm antibodies: their role in infertility. Fertility & Sterility 42, 171 -183.
Millar, S.E., & Dean, J. (1993). Targeting the zone pellucida for immunocontraception. In R.K. Naz (Ed.). Immunology of reproduction, Cha. 14, pp. 293-313. Boca Raton, FL: CRC Press.
Moss, B., Smith, G.L., Gerin, J.L., & Purcell, R.H. (1984). Live recombinant vaccinia virus protects chimpanzees against hepatitis B. Nature 311, 67-69.
Please address correspondence to Dr. Hall, Professor Emeritus of Microbiology 5326 Keikilani Circle, Honolulu, HI 96821-1515.
Population and Environment: A Journal of Interdisciplinary Studies Volume 18, Number 1, September 1996 1996 Human Sciences Press, Inc.